Jhye Richardson said Australia's bowlers will be looking to improve their execution in the death overs after missing their lengths in the heavy defeat to New Zealand at Hagley Oval in the first T20I of the five-match series.

New Zealand had slumped to 19 for 3 in the Powerplay after being sent in to bat, with Daniel Sams and Richardson bowling superbly upfront.

However, Australia's bowlers conceded 76 runs in the last six overs of the innings and 33 off the last two, as Devon Conway produced a stunning 99 not out to lift New Zealand to a winning total of 184 for 5.

Richardson was the pick of Australia's quicks claiming 2 for 31 on his return to the T20I side. He only bowled one over in the last four, picking up the wicket of James Neesham, but he did admit he didn't quite hit his lengths, conceding a six each to Conway and Glenn Phillips in his four overs.

"I think from a personal point of view I certainly missed my length," Richardson said. "I think they batted really well. The outfield was exceptionally fast. It got a little bit dewy at the end so we found the ball was probably skidding on a little bit more at the end as to the start of the innings which probably helped them a little bit, just in terms of slower balls not sticking into the wicket as much as they were earlier.

"If we missed our length we got punished. I think the planning and everything from that aspect was fine. We were all satisfied with how we went about our planning and the decisions made out there. It just comes down to an execution thing."

Australia were then surprised that the ball swung as prodigiously as it did for New Zealand under lights after the dew had settled in with Trent Boult and Tim Southee ripping through the top order to leave them 19 for 4.

"They just kept it really simple, didn't they?" Richardson said. "How often do you see three slips in a T20? We probably didn't expect the ball to swing for that long and that much, to be honest. [It] didn't really swing too much in our innings.

"It was a little bit of a surprise but knowing that now, it's something we'll keep in the back of our mind going into the next game. [Boult and Southee are] two class bowlers and we saw them keep it really simple while the ball was swinging, just bowling a really nice line and length and making us make mistakes."

Richardson was pleased to be back playing at the international level. It was just his second appearance for Australia since his shoulder injury in 2019, and his first in 12 months after missing Australia's tour to England and the ODI and T20I series against India before Christmas. He spoke in the build-up about trying to take some pressure off himself after struggling with the weight of his own expectations at the end of the BBL.

"I think I had plenty of time between the end of the Big Bash and now to think about how I was going about my last few Big Bash games, putting myself under a lot of pressure," Richardson said.

"I had a lot of time to think and reflect on that and went into the game really wanting to enjoy myself and not put myself under so much pressure because I know what I've done to get to this point. I can trust that.

"I just went out there yesterday with the sole focus of just trying to enjoy myself and certainly did."